The present invention relates generally to the field of containers. More particularly, this invention relates to single service beverage containers exhibiting internal pressures greater than the ambient pressure. Such containers are typically used with carbonated beverages.
Various types and styles of containers and caps have been used where the internal pressure of the container exceeds that of the surroundings. Containers exhibiting positive internal pressures are commonly encountered in the field of carbonated beverages and typically employ either a "pop-top" or removable cap. Typical of those containers having a plastic cap, is that the cap is "torn-off" or separated from a member which indicates whether the container has been tampered or previously opened.
One common variety of the caps used in the above situation is the threaded cap. This cap exhibits threads on the interior of a skirt portion that extends downwardly over a threaded neck portion of the container body. In these containers, the cap is frictionally engaged and retained by the threads to the neck of the bottle. Generally, an indicating ring is provided at the lower end of the cap. The ring separates from the cap when the container is opened and thereby indicates tampering.
While the above style caps work well with narrow necked container bodies or bottles, these caps have not been successfully applied to a wide-mouthed plastic can-type of container.
With this in mind it is an object of the present invention to provide a novel container for use in positive internal pressure applications, particularly with carbonated beverages.
An additional object of this invention is to provide a closure cap for wide mouthed container bodies.
It is an object of the invention to produce a container having indicia for evidencing tampering with the container.
Another object of the invention is to produce a single service container wherein the cap remains attached to the container body once the container has been opened.
It is a further object of the present invention to provide a container wherein the internal pressure of the container cooperates with the cap to assist in sealing the container.
In view of these above objects, the present invention provides for a plastic container having a hollow body with a mouth formed at its upper end and a closure cap which engages the mouth to seal the container.
Formed on the interior of the mouth is a conical or tapered annular surface which generally narrows in the outward direction of the opening formed by the mouth. Extending generally toward the interior of the container body, the centralmost portion of the cap is a generally downwardly concave domed portion which terminates at its perimeter in a frustro-conically shaped ring. The frustro-conical ring engages the tapered surface of the mouth's interior. The closure cap is mounted to the container body by a snap-on type of engagement. Prior to mounting, the cap is in a generally inverted or cup shaped position. In otherwords, a skirt depending from the frustro-conical ring extends upward therefrom resulting in what has been referred to as an "over-center" sealing mechanism. In mounting, the cap is positioned over the mouth of the container body and the skirt is moved from its upward extending position to a downward extending position causing the cap to tighten itself into a sealing engagement on the mouth. Once mounted, the internal pressure of the container urges the domed portion upward causing the frustro-conical ring to engage the tapered surface of the mouth in substantially surface to surface contact thereby assisting in sealing the container.
Also included on the cap, and in particular the skirt portion, is an indicia mechanism for indicating whether the container has been previously opened or subjected to tampering. In one embodiment, a tear strip is circumferentially provided in the skirt. In opening the container, the tear strip is permanently severed from the skirt around the neck of the bottle. The torn strip readily indicates if the container has been tamper with or previously opened.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiments and the appended claims, taken in conjunction with the accompanying drawings.